This invention relates generally to toilet articles, and more particularly to toilet articles having a plurality of layers of different materials separated by at least one pre-formed membrane.
Solid toilet articles in the form of bars, cakes or sticks have been commercially available for many years. These articles may consist of soaps, detergents, antiperspirants, deodorants, and cosmetics and may contain various other substances such as colouring materials, perfumes, benefiting agents, moisturisers and fillers. Different product formulations are used to accomplish different personal care needs. For example, skin on some parts of the body may be more sensitive than other areas. Some body areas are also more prone to perspire than other areas. In addition, the hands are more often exposed to more hard to remove dirt and grease than the rest of the body. These divergent personal care problems have lead to the production of different toilet articles designed for such different needs. Moreover, various individuals in the household may have different preferences or needs so that the household may keep on hand, at the lavatory or the shower, several different personal care articles.
European Patent Application No. 366209 titled xe2x80x9cMethod of Production of Tablets of Toiletxe2x80x9d, published May 2,1990, and U.S. Pat. No. 4,996,000 titled xe2x80x9cMulti-Layer Cleansing Barxe2x80x9d, issued to Dale R. Redeker on Feb. 26, 1999 both disclose a cast moulded cleansing bar having a plurality of layers of different cleansing materials. U.S. Pat. No. 5,198,140 titled xe2x80x9cDual Composition Toilet or Detergent Bar Containing Convoluted Surfaces and Tongue and Groove Interlockxe2x80x9d issued to David Joshi et al., on Mar. 30, 1993, discloses an extrusion formed dual composition bar. Japanese Patent Kokai Application No. 59-157200, published in Sep. 6,1984, discloses a two phase toilet bar. This two phase bar is made by melt casting a first cleansing composition, removing the first casting from the mold, spraying with coloring pigment, cutting the casting to shape a decorative curve, repositioning the cut first casting in a mold, and casting a second cleansing composition, which adheres to the first cleansing composition layer, to form a two phase bar with a curvilinear boundary layer. U.S. Pat. No. 5,217,639 titled xe2x80x9cDual Phase Toilet Bar Containing a Clear Portion and an Opaque Portion Joined Along a Single Curvilinear Shaped Surfacexe2x80x9d issued to Nicolas Mottola on Jun. 8, 1993, discloses a dual phase toilet bar. The bar is cast by a sequential molding technique wherein a first molten toilet composition is poured into a plastic mold filing the mold to the 50% mark, allowed to harden, and then a second molten toilet composition is poured into the mold and subsequently allowed to harden. One disadvantage of this molding technique is the variability of the boundary line that is obtained between the two cleansing materials. Japanese Patent Kokai Application No. 08-60198, published in Mar. 5, 1996, discloses a multi-phase toilet bar integrated with adhesives. A disadvantage to making this toilet bar is the complicated production process where the individual phases must be cast, adhesive applied, and then joined together until the adhesive sets.
U.S. Pat. No. 4,202,879 titled xe2x80x9cThree Phase Antiperspirant Stickxe2x80x9d issued to David Shelton on May 13, 1980, discloses a three phase antiperspirant stick with concentric zones of an antiperspirant and deodorant compositions separated by a shearable wax layer. A disadvantage to making this stick is the complicated production process where the inner phase must be dipped in wax before being cast with the outer phase.
None of the foregoing patents however, disclose a toilet article with multi-layers, each separated by a thin membrane, which is preformed by either solution or dispersion casting, molding, extrusion or other suitable techniques. This membrane may be used to control the shape of each layer reproducibly in a multi-layer toilet article such that the shape of the boundary layer can be custom made and is consistent from article to article. Another potential advantage of the membrane is the separation achieved between the layers such that there is little or no migration of one layer into the other. A distinct drawback of toilet articles that are cast without formed dividers is that they may display random variation with the position of the boundary between the different layers.
In one aspect, the present invention relates to a multi-layer toilet article containing a plurality of layers of materials, with at least two layers separated by a preformed membrane material. This provides distinct and highly reproducible lines of separation between the layers or phases. In another aspect of the present invention, a multi-layer toilet cleansing bar is provided that functions similarly to conventional toilet bar and its cleansing activity yet can provide skin benefits associated with different cleansing material compositions which are placed in at least two distinct layers of the bar, separated by a preformed membrane. In another aspect of the invention, a multi-layer antiperspirant-deodorant stick is provided that functions similarly to a conventional antiperspirant stick yet can provide skin benefits associated with deodorant or other material compositions which are placed in at least two distinct layers of the stick, separated by a preformed membrane. In another aspect of the invention, a multi-layer cosmetic stick is provided, such as a lipstick or the like, which can incorporate a plurality of colored and/or textured materials which the user may select alone or in combination according to personal preference, and where such a plurality of materials are placed in at least two distinct layers of the cosmetic stick, separated by a preformed membrane.
A further aspect of the present invention is to provide a multi-layer toilet article wherein certain active ingredients are incorporated into one layer but not in the other. The ingredients in one layer may or may not be compatible with the ingredients in an adjacent layer separated by the preformed membrane. A still further aspect of the present invention is to provide a continuous or batch process for manufacturing a multi-layer toilet article wherein a highly reproducible plurality of boundary layers is obtainable, and which remain distinct with use. These and other aspects of the present invention will become more apparent from the detailed description and examples that follow.